Head and body length of N. narica is
410-670 mm, tail length is 320-690 mm. Height at the shoulder
is about 305 mm, and weights range from 3-6 kg. Males are
usually larger than the females. The pelage is fairly long
and fairly coarse. Coloration is reddish brown to black with
yellowish to dark brown below. The muzzle, chin, and throat
are usually whitish. The feet are nearly black, there black
and gray markings on the face, and the semi-prehensile tail
is banded. N. narica has a long, pointed muzzle. The
forelegs are short, the hind legs long, and the tail is longer
than the body.

N. narica is found mainly in wooded areas and forages
both on the ground and in the trees. While travelling on the
ground, the tail is held erect and the tip is curled. Probing
of crevices and holes is done with the long, movable snout.
N. narica is diurnal, but adult males are mostly active
during the night. The quest for food can take them 1,500-2,000
meters each day, after which coatimundis find a tree to roost
in for the rest of the night. During the season when fruit
is abundant N. nasua eats almost nothing else. At other times
of the year females and young will look for invertebrates
on the forest floor and adult males prefer large rodents.

The social structure of N. narica usually consists
of females and young up to two years of age in a loosely banded
group of 4-20 individuals. Males over two years are solitary,
except during the breeding season. At this time the males
may enter the group of females and their other offspring,
remaining completely subordinate to the adult females. The
breeding season coincides with the greatest abundance of fruit
due to the great amount of competition for food between the
large males and the rest of the group. It may also deter the
males from preying on the baby coatis during the time of year
that their diets become primarily carnivorous.

N. narica breeds once each year and the gestation period
is 10-11 weeks. When a female becomes pregnant she leaves
the group and constructs a tree nest where she gives birth
to between 2 and 7 offspring. The babies weigh 100-180 grams
at birth, open their eyes at 11 days, and are weaned at 4
months. At five weeks old the babies leave the nest and join
the group with their mother. They are fully grown at 15 months
and reach sexual maturity at 2 years of age.